[C3 glomerulopathy]

Abstract

C3 glomerulopathy includes C3 glomerulonephritis, Dense Deposit Disease, Factor H-Related Protein 5 (CFHR5) nephropathy and most atypical acute postinfectious glomerulonephritis. The characteristic of this nephropathy is C3 deposits without immunoglobulins. Light microscopy pattern can be mesangial proliferative or membrano-proliferative. A dysregulation of complement is at the base of the disease: acquired changes (autoantibodies anti-C3 convertase -C3 Nephritic Factor-, anti-factor H, I or B) or genetic changes (mutations of factors B, H, I, or 1-5 Factor H-related proteins) are found. Targeted treatments are directed towards replacement of lacking factors with plasma or to removal of antibodies with plasma exchange or towards control of complement functioning. In particular eculizumab, a humanized monoclonal antibody directed against C5, has been shown to have a favourable effect in anecdotal cases and in a small series of patients in a prospective study. Corticosteroids and immunosuppressive drugs are ineffective. Further studies on this nephropathy will define characteristics and indicate the most suitable treatment options.